Anxiety cannot cause permanent brain damage so yes it is absolute rubbish.

Sounds like you are on a typical anxiety spiral. I am one stage ahead of that on my anxiety journey in that I have understood and can accept the anxiety - I think there are three main stages of an anxiety disorder. Firstly the actual anxiety disorder triggered by whatever event (in my case a series of panic attacks which developed into a panic disorder) then move onto the second phase which in whatever way they can either through self help or therapy they come to an understanding of the problem, what exactly is causing it and critically realising that anxiety is harmless and they then stop fearing it and accept it as a part of their life and then the third stage which is resolution and this comes naturally over time and exposure. Exposure to anxiety provoking situations is key and exposing yourself to the anxiety with the new found tolerance of the anxiety found in stage 2 will gradually eliminate the anxiety all together.